Consider format as you evaluate

Format impacts what you can glean from a source,and possibly your ability to utilize it.

Professional historians often travel to use archival sources in their original format and language. This usually isn't practical for students, but bear these things in mind.

Original
manuscripts may contain handwritten notes in the margins (or other useful info) that a published copy
lacks.

Edited and translated works are subject to possible errors and biases of editors and translators.

Digital copies need particular scrutiny. They may contain transcription errors, may not
reliably represent the original source, or may be of dubious origin
(incomplete citation). After all, anyone can post something online.